Figure 1  .

Representative fluorescein clearance test (FCT) results of normal tear secretion and clearance (a, b), severe aqueous tear deficiency (c, d), mild aqueous tear deficiency (e, f), unilateral (left eye) delayed tear clearance (g, h), and bilateral delayed tear clearance (i, j). For each case, six sets of Schirmer paper strips were used in a period of 30 minutes, with one set per 5 minute interval. For each set, the first and second strip was obtained from right and left eye, respectively. The detail of how FCT was performed is given in the Methods section. The entire six sets of strips were taped onto the record card with the wetting length marked by pencil (left panel), and the fluorescein intensity can be better appreciated when photographed under blue light (right panel).